Conventional tape heads as currently used to tape or seal cases or cartons are designed to apply a reasonably strong force on the tape to better ensure a strong bond between the tape and the case or carton. Conventionally most cartons that are taped to seal them on case sealing machines are made from corrugated paperboard that is generally a laminate of two opposed surface layers or liners with a corrugated layer sandwiched therebetween and adhered to each liner which provides a material of sufficient strength for the intended use. Even when the case or carton is made of such material and is not properly or fully filled care must be exercised to ensure the pressure applied during sealing does not unduly deform the closure flaps of the case being sealed as the tape is being applied. This problem of deforming the case or flaps is exacerbated when the case is made of flimsier material and particularly when such a case or carton is not properly filled which normally results in what is referred to as a soft case or carton of the like.
Distortion of the carton closure flaps is a problem that on-line shopping and resulting shipping has magnified significantly and one of was proposed to help solve tis problem requires reduction of the pressure applied to the closure flaps of the case or carton during the taping operation.
Signode U.S. Pat. Nos. 9,517,914 and 9,630,796 provide examples of a device specifically designed to try to overcome this problem and uses a pair of pneumatic cylinders one to reduce pressure applied against the top (as opposed to the ends) of the carton or case to which a sealing tape is being applied by the tape application rollers and a second to reduce pressure applied by the cut-off mechanism of the tape applicator or tape head. The earlier of these 2 patent relates specifically to reducing the pressure applied to by the wipe down roller and the later one to reducing the pressure applied by the cut-off mechanism. As indicated each uses a dedicated pressure cylinder to reduce pressure being applied.
US application 2013/174962 uses a sensor to sense the position of a carton to which a sealing tape is being applied and activate a pressure cylinder to raise and lower the tape applying and pressing rolls to apply different pressures to the tape and thereby the to the carton.
U.S. Pat. No. 9,061,857 increases the spring tension in stages to reduce the forces applied to the leading face of the case being taped with the increased tension being generated using a bar that presses against the case.
Chinese patent CN102092497 uses a pressure cylinder to position the application and pressure roller of the tape applicator. Japanese patent JP4265745 connects a cylinder to the trailing or wipe down arm and another cylinder connects to the cut-off mechanism each via a lost motion connection
U.S. Pat. No. 5,338,384 uses a pressure cylinder to change the pressure applied to the rollers more particularly to increase the pressure to the wipe down roll when wiping the tape onto the trailing face of the carton.
US patent application 2018/022492 also uses a pressure cylinder to adjust the pressure applied to the case being sealed to apply less pressure to the top of the case.
It is also known that devices used to apply what are know as L-clips to seal the flaps by applying short lengths of tape to the flaps adjacent the opposed ends of the flaps so there is no tape application over a significant central portion of the flaps using a cylinder to direct the tape towards the knife to be cut, see, for example, U.S. Pat. No. 8,176,959 issued May 15, 2012 to Lam or German patent DE3820060 both of which manipulate the push bar connecting the front application roll and back wipe down roller to move them way from the box or case between the applications of the L-clips. These devices are not designed to reduce pressure on the case or carton rather the applicator roll is moved up to bring the tape towards the knife for cutting.
None of the reference found to-date teach a simplified system of the present invention wherein an actuator is used to increase the pressure applied to the carton or case by the wipe down roll and the cut-off mechanism at the appropriate times